Matter Christian M, Schuler Pia K, Alessi Patrizia, Meier Patricia, Ricci Romeo, Zhang Dongming, Halin Cornelia, Castellani Patrizia, Zardi Luciano, Hofer Christoph K, Montani Matteo, Neri Dario, Lüscher Thomas F
Cardiovascular Research, Institute of Physiology, University of Zurich and Cardiovascular Center, Zurich University Hospital, Switzerland.
Circ Res. 2004 Dec 10;95(12):1225-33. doi: 10.1161/01.RES.0000150373.15149.ff. Epub 2004 Nov 11.
Current imaging modalities of human atherosclerosis, such as angiography, ultrasound, and computed tomography, visualize plaque morphology. However, methods that provide insight into plaque biology using molecular tools are still insufficient. The extra-domain B (ED-B) is inserted into the fibronectin molecule by alternative splicing during angiogenesis and tissue remodeling but is virtually undetectable in normal adult tissues. Angiogenesis and tissue repair are also hallmarks of advanced plaques. For imaging atherosclerotic plaques, the human antibody L19 (specific against ED-B) and a negative control antibody were labeled with radioiodine or infrared fluorophores and injected intravenously into atherosclerotic apolipoprotein E-null (ApoE-/-) or normal wild-type mice. Aortas isolated 4 hours, 24 hours, and 3 days after injection exhibited a selective and stable uptake of L19 when using radiographic or fluorescent imaging. L19 binding was confined to the plaques as assessed by fat staining. Comparisons between fat staining and autoradiographies 24 hours after 125I-labeled L19 revealed a significant correlation (r=0.89; P<0.0001). Minimal antibody uptake was observed in normal vessels from wild-type mice receiving the L19 antibody and in atherosclerotic vessels from ApoE-/- mice receiving the negative control antibody. Immunohistochemical studies revealed increased expression of ED-B not only in murine but also in human plaques, in which it was found predominantly around vasa vasorum and plaque matrix. In summary, we demonstrate selective targeting of atheromas in mice using the human antibody to the ED-B domain of fibronectin. Thus, our findings may set the stage for antibody-based molecular imaging of atherosclerotic plaques in the intact organism.
目前用于检测人类动脉粥样硬化的成像方式，如血管造影、超声和计算机断层扫描，能够显示斑块形态。然而，利用分子工具深入了解斑块生物学特性的方法仍显不足。在血管生成和组织重塑过程中，通过可变剪接，额外结构域B（ED-B）被插入到纤连蛋白分子中，但在正常成年组织中几乎检测不到。血管生成和组织修复也是晚期斑块的特征。为了对动脉粥样硬化斑块进行成像，将人源抗体L19（特异性针对ED-B）和阴性对照抗体用放射性碘或红外荧光团标记，然后静脉注射到动脉粥样硬化载脂蛋白E基因敲除（ApoE-/-）小鼠或正常野生型小鼠体内。注射后4小时、24小时和3天分离的主动脉，在使用放射成像或荧光成像时，显示出L19的选择性和稳定摄取。通过脂肪染色评估，L19的结合局限于斑块。125I标记的L19注射24小时后，脂肪染色与放射自显影之间的比较显示出显著相关性（r=0.89；P<0.0001）。在接受L19抗体的野生型小鼠的正常血管以及接受阴性对照抗体的ApoE-/-小鼠的动脉粥样硬化血管中，观察到的抗体摄取极少。免疫组织化学研究表明，ED-B不仅在小鼠斑块中，而且在人类斑块中表达增加，在人类斑块中，ED-B主要存在于滋养血管和斑块基质周围。总之，我们证明了使用针对纤连蛋白ED-B结构域的人源抗体可在小鼠体内选择性靶向动脉粥样瘤。因此，我们的发现可能为完整机体中基于抗体的动脉粥样硬化斑块分子成像奠定基础。
